Hurricaneman wrote:What the GFS has been doing through the last few days of runs is splitting the wave in two sending one piece north of PR while the southern half forms in the western Caribbean on a later date, my thinking is something forms in between
The reason the GFS splits the energy is due to an upper-low that will be forming and then dipping SW into its way. It's actually pretty similar to Ian's setup except the upper-low with Ian was slower and paralleled it, while this one wants to dive down and pinwheel the energy north. This interaction can cause widely different solutions. On the latest GEFS, The faster ensemble members move this into the Caribbean while the slower members interact with the low and move it north.